Known in the prior art are low-power brushed electric motors with built-in filters for suppressing electromagnetic noise due to motor operation and a motor power supply circuit, in particular for powering the commutator attached to the rotor. The filters and power supply circuit are mounted between the motor casing and cover.
The commutator is powered by the power supply circuit which comprises brushes mounted in suitable holder sleeves along which they are pushed towards the commutator by springs which contribute to brush wear.
The brushes are connected to the external power supply by a braided conductor, normally of copper, and noise is suppressed by simple inductors connected in series with the brushes.
These motors have operating temperature limits in that they cannot operate at temperatures greater than 80°-85° without drastically reducing performance and, moreover, they are not satisfactory in terms of electromagnetic compatibility (EMI) because there is very little space inside them for filters other than the basic, and not very sophisticated, traditional inductors.
These aspects are even worse in the case of a sealed motor because the heat that develops inside the motor cannot be removed by forced air flows.
Another shortcoming of these motors is due to the presence of the braid, which must be especially soldered to the power supply circuit.